Multiple section paper tube and method of making same



E. S. REID May 26, 1959 MULTIPLE SECTION PAPER TUBE AND METHOD OF MAKING SAME Filed Dec. 21, 1.956

Fig. 3

INVENTOR. :mWARD S- "5/0 BY 1 W 6 60(4406 A fromvsns United States Patent MULTIPLESECTION PAPER TUBE AND METHOD OF MAKING SAME Edward S. Reid, Hartsville, S.C., assignor to Sonoco Products Company, a corporation of South Carolina Application December 21, 1956, Serial No. 629,918

Claims. (Cl. 138-78) This invention relates to paper tubes and more particularly to a paper tube wound into two or more separable concentric components by spiral winding.

Heretofore, in the manufacture of paper tubes of different diameters, a separate winding operation for each tube was required.

In accordance with the present invention, a paper tube is provided that has at least two separable concentric components and one winding operation effectively winds the two or more concentric components of different diameters into a single multiple component paper tube. Each of the two or more separate components of the paper tube is formed from one or more spirally wound paper plies, to which adhesive is applied during the winding operation. To produce the separable tube components, adhesive is omitted along a winding surface between two or more adjacent plies, thereby forming an unbonded surface at the juncture of the separate components which are detachably joined.

To separate the tube components thus formed, endwise pressure is applied to one of the components while holding the other component stationary. This causes rupture of the unbonded paper plies and permits endwise movement and separation of the concentric tubes to form two, or more, separate tubes.

The separated tubes can then be used for any and all purposes for which separately made tubes are commonly used, including uses in the construction field. The tubes may be used as forms for pouring of new complete concrete columns, or may be used around existing structures such as steel columns, for pouring a concrete column therearound as disclosed in my copending application Serial No. 601,187, filed July 31, 1956. In the latter case the composite tube or the separated tubes may be slit longitudinally for placing around the existing structure.

These and other features of the present invention are described in further detail below in connection with the accompanying drawings in which:

Fig. 1 is a perspective view of a paper tube embodying the present invention composed of two separate components;

Fig. 2 is a top plan view of the paper tube shown in Fig. 1; and

Fig. 3 is a sectional detail illustrating the plies of the paper tube components.

Referring now in detail to the drawings and more particularly at first to Figs. 1 and 2, the paper tube of the present invention is indicated generally by the numeral and is composed of an inner component 12 and an outer component 14. The double component paper tube is used merely for the purpose of illustration, it being understood that a paper tube with any number of components can be formed by my invention.

Figure 3 discloses each of components 12, 14 formed from three spirally wound plies with an adhesive 16 applied to the winding surface of the plies. Adhesive 16 is omitted at the winding surface 18 between components 12, 14 and an unbonded surface is therefore formed at the juncture of the components producing the separable components 12, 14.

The components 12, 14 may be formed of any desired number of plies, the triple ply components disclosed being only one form of my invention. Since no adhesive is applied to the winding surface 18 located between components 12, 14, component 14 can be easily separated from component 12. This can be accomplished by suitable means such as a plunger member exerting endwise pressure on the inner component 12 while holding outer component 14 stationary thereby moving inner component 12 relative to outer component 14.

The multiple component paper tube is formed in one winding operation by spirally winding a plurality of paper strips about a mandrel to form a laminated or multi-ply tubular body 10 of the necessary length and wall thickness. The spirally wound paper strips are bonded by a suitable adhesive, such as sodium silicate, applied to one surface of the strips as they are wound. Adhesive is usually applied to the inner surface of each strip except the innermost strip of the paper tube. In the present invention, however, adhesive is not applied to the winding surface between two or more adjacent intermediate plies, thereby forming at least one intermediate unbonded surface that allows two or more separate components to be formed in one winding operation. If it is desired to have more than two components, more than one intennediate unbonded winding surface between adjacent plies would have to be provided. The winding operation for my multiple component paper tube is similar to the winding operation for a spirally wound paper tube having only one component, except for omitting the adhesive between two or more adjacent plies.

In the spirally wound structure of the completed paper tube 10, the adjacent plies are superimposed by spiral winding with butt joints in staggered relation or with overlapped joints (the latter not shown). It is usual in butt joints of a spirally wound construction to have some spacing between the adjacent edges at the joint. In some instances, it may be advantageous to wind all plies with butt joints except the final exterior ply, which is usually applied with an overlapped joint for presenting a smooth outer surface.

The present invention has been described in detail above for purposes of illustration only and is not intended to be limited by this description or otherwise except as defined in the appended claims.

I claim:

1. A composite paper tube comprising a plurality of concentric components, each component having a plurality of concentric spirally wound paper plies with an adhesive applied to the winding surface between adjacent plies, the winding surface between adjacent components having no adhesive thereby forming an unbonded surface at the juncture of the separate components, said components being detachably joined and easily separated by applying endwise pressure to one of said components while holding the remainder of the components stationary.

2. A dual component paper tube comprising a plurality of concentric spirally wound paper plies with an adhesive applied to the winding surfaces between adjacent plies but being omitted at one winding surface between two adjacent plies thereby forming an unbonded intermediate surface dividing the paper tube into two separate components that are detachably joined and easily separated by applying endwise pressure to one of the components while holding the other component stationary in its original position;

3. A method of forming paper tubes having concentric multiple components comprising spirally winding a plurality of paper plies on each other, applying an adhesive to the paper plies so that all of the contacting surfaces between adjacent plies have an adhesive thereon except at least one contacting surface thereby forming at least one unbonded intermediate contact surface and separate components, and applying endwise pressure to one of the components while holding the remainder of the components stationary thereby rupturing the unbonded paper plies and permitting endwise movement and separation of the components to form at least two separate components.

4. A composite paper tube comprising a plurality of concentric components, each component having a plurality of concentric spirally Wound paper plies with an adhesive applied to the winding surface between adjacent plies, the winding surface between adjacent components having no adhesive thereby forming an unbonded surface at the juncture of the separate components to permit separation of said components.

References Cited in the file of this patent UNITED STATES PATENTS 2,465,257 Nebasar Mar. 22, 1949 

